STABILITY AND SENSITIVITY ENHANCEMENT USING ETV-ICPMS

The interfacing of an electrothermal vaporization (ETV) unit to an ind uctively coupled plasma mass spectrometer (ICPMS) produces a powerful system for ultra-low-level compositional analysis of micro-volume samp les, as well as decreasing some of the molecular interferences inheren t in a conventional-nebulization ICPMS. Some problems still remain wit h this technique in respect to signal variation, sample heating profil es, and instrument tuning parameters. Advances are presented concernin g the instrumental conditions necessary for lowering signal variation. These include optimization of ''dry-plasma'' tuning of the spectromet er lens stack, furnace cooling/heating, and tube mounting. Novel ways of enhancing sensitivity by multiple deposition, preconcentration, and chemical modification have been investigated with particular emphasis on uranium and radium determination.